Bug#952628: hepmc3: FTBFS: Feature.h:296:69: internal compiler error: in get_fns, at cp/tree.c:2455

[Frank Siegert <frank.siegert@cern.ch>]

While this has been re-assigned to gcc as a compiler regression, let
me just mention for the HepMC3 maintainers, that there is a workaround
from the authors which makes HepMC3 compile again:

  https://gitlab.cern.ch/hepmc/HepMC3/-/commit/ba38f14d8f56c16cc4105d98f6d4540c928c6150

(That patch is for HepMC 3.2.1, but given the error looks the same it
probably also applies to 3.1.2 which you have in Debian.)

Best,
Frank

PS: This is also being used in the Archlinux package now and fixes the
same compilation issue there
(https://aur.archlinux.org/packages/hepmc3/ -> View PKGBUILD).